Sigma - IC3-Modbus reading Long or 32-bit data values.

Issue

To read "Long" or 32-bit values with an IC3-Modbus.

Product Line

Satchwell Sigma

Environment

Sigma

IC3 - Modbus

Modbus

Long

Data

32-bit

Cause

Both "Long" and 32-bit data values can be stored in two separate 16 bit registers and this data must be added together to give the correct reading.

Resolution

To read "Long" or 32-bit data, which is stored in two registers, it is necessary to carry out the following;

Configure the Gateway.txt file entry -

Object No,controller No,Function code,Reg address,Poll Time,No of registers to call,Min,Max,Hardware.

An example could be 50,1,3,4000,1,2,0,0,1

In the controller Sigma AI objects would be created, in the case above, these would be 50 and 51.

A programmable object is required to present the final reading, please see the example below.

10 XFlo = POINT 0|50
20 YFlo = ( POINT 0|51 * 65536.0 )
30 ZFlo = ( XFlo + YFlo ) / 100.000
40 RETURN VIA TEXT 92 VALUE ZFlo

The above programme assumes that the value has been multiplied by 100 at the source device.

The object numbers match the example given and the correct short text number is required.